Proth Search Page |

Primes k · 2 + 1 ^{n} |
List of primes for k < 300
List of primes for 300 < k < 600
List of primes for 600 < k < 900
List of primes for 900 < k < 1200
Frequencies (draft) History (under preparation) |

Fermat numbers |
Standard factoring status
Factors of generalized Fermat numbers GFN03 factoring status GFN05 factoring status GFN06 factoring status GFN07 factoring status GFN10 factoring status GFN11 factoring status GFN12 factoring status Search limits and reservations |

Primes k · 2 − 1 ^{n} |
List of primes for k < 300 |

The Sierpiński problem |
Definition and status |

The Riesel problem |
Definition and status |

Cullen primes |
Definition and status |

Woodall primes |
Definition and status |

Generalized Fermat number GF(25,10) proved composite.

July 15, 2019:

Lists of primes

all currently known primes included.

New factors at GFNfacs.html:

now includes 6618 new divisibilities (10 found in 2019).

July 6, 2019:

Generalized Fermat number GF(24,10) proved composite.

March 23, 2019:

New factor of Fermat number F(9863).

January 28, 2019:

New factor of Fermat number F(118).

December 19, 2018:

New factor of Fermat number F(132).

December 13, 2018:

New factor of Fermat number F(3345).

November 2, 2018:

New factor of Fermat number F(2144).

July 24, 2018:

New factor of Fermat number F(5199).

It brings to 300 the total number of known composite

Fermat numbers.

May 1, 2018:

New factor of Generalized Fermat number GF(10746,12).

April 5, 2018:

New factor of Fermat number F(274).

April 3, 2018:

Candidate of Extended Sierpinski Problem eliminated.

March 10, 2018:

New factor of Fermat number F(63480).

January 15, 2018:

New factorization at GFNsmall.html:

Cofactor of 11^(2^8) + 10^(2^8) is P62 × P107 .

December 30, 2017:

Riesel problem candidate eliminated!